The present invention relates to an insert and a holder of a cutting tool. More particularly, the insert is brought into engagement with the holder with concave and convex grooves to provide a secure engagement.
Conventionally, there is a cutting tool 104 in which an insert 102 having a basic form of parallelogram is detachably mounted by a clamp screw 103 as a clamping member on a tip mounting face 101 of a holder 100 (see FIG. 8). The holder 100 of this cutting tool 104 has the flat tip mounting face 101 provided with a female thread hole 105 into which the clamp screw 103 is screwed, and a restricting wall 106 protruding on the tip mounting face 101, for restricting the movement of the insert 102 at two sides of the insert 102. Such a cutting tool 104 is mainly employed for cutting-off, grooving, cutting with a saw, and thread cutting work, in which a force applied on the insert 102 at the time of cutting is supported on the restricting wall 106 of the holder 100.
Usually, the insert 102 having a basic form of a parallelogram is provided with the cutting edges 102a in two corner portions of acute angle that are located in point symmetry around the clamp screw 103, and when one cutting edge 102a is worn, the other cutting edge 102a is used by rotating the insert 102. Further, the cutting edge 102 rotated on the backside makes contact with the restricting wall 106 of the holder 100 to restrict the movement of the insert 102.
By the way, the cutting edge 102a of the insert 102 may be broken during the cutting work. Particularly, because the insert 102 for cutting-off or grooving work has a thinner cutting edge portion, as shown in FIG. 8, most of the cutting edge 102a may be possibly broken away. When rotated on the backside, the cutting edge 102a has an important role of making contact with the restricting wall 106 of the holder 100 to restrict the movement of the insert 102. Thereby, if that portion is missing, the restricting force of the insert 102 is weakened, and the cutting tool may possibly become unusable.